Baby Crabs Invade Cayman Islands

"Supermoon" and low tides could have made it easier for the crabs to reach land

By DANICA COTO •Published May 17, 2012•Updated on May 17, 2012 at 6:27 am

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Hundreds of thousands of red baby crabs are invading the Cayman Islands in a seasonal migration that residents say is unusually heavy this year.

The crabs are blanketing roads, scurrying across yards and scratching their way up homes and buildings in a process that scientists say will last about a month.

"People living in the coast will have them everywhere," said Tim Austin, deputy director of the Cayman Islands' Environment Department, on Wednesday. "They get in houses, into your AC system. Anywhere there's a gap, they'll find it. They're trying to get somewhere where they'll live happily."

The baby crabs, which are smaller than a thumbnail, were born in the ocean a few weeks ago and are emerging along rocky shores, seeking forests and wetlands near the coast where they will remain until they reproduce and head back to sea to deposit their eggs, Austin said. While the babies are red, the species is known as the black land crab because of the dark purple color it takes on as it ages.

It is likely that the recent "supermoon" and low tides have made it easier for the baby crabs to reach land, which could help explain the increase this year, he said. Most of them are overrunning Cayman Brac and Little Cayman, two of three islands that make up the archipelago.

The baby crabs do not migrate every year, in part because of ocean currents, tides and wind conditions, but adult crabs migrate every year to the ocean during the start of the rainy season, usually in May. Their migration has already occurred.

The government urges people to try to avoid the crabs as they drive, but it is nearly impossible not to hit them.

"It's a minefield of flattened crabs. You'll just see hundreds of splats," said Jim Andrews, 48, who lives with his family in the southeast end of Grand Cayman.

His house has been invaded by crabs as well.

"This year, we just saw tons of the tiny little newborns," he said. "You can hear them crawling on the windowsills."

Andrews said his two young boys know better than to play with the adult crabs. His dog, not as much.

"The dog likes to grab them and twirl them around and throw them around," he said. "She knows she might get bit. Not bit, clawed."

The migration of the adult crabs occurs at night, and the crabs, which grow up to 1 foot (0.3 meters) long, have been blamed for causing flat tires.

"Crabs will see the cars coming. They'll hunker down and put their claws up," said James Gibb, research officer with the Environment Department. "A colleague of mine went through four tires five years ago."

Adult crabs also can move up to six feet (two meters) per second, Austin said.

"This is why they are hard to miss on the roads," he said. "You line your car up to miss them, and then they suddenly dart back into your path."

The adult crabs also lead to another yearly problem: the theft of garbage bins.

People will hunt the crabs at night with flashlights and place them in stolen garbage bins where they'll feed them mangos and vegetables to clean their system before cooking them, Gibb said.

"My dad will get upset," he said, referring to the yearly theft. "I have to go to the hardware store and buy new garbage bins."

But Gibb said he doesn't mind living in the middle of what he calls the "red tide".

"You're closer to nature," he said. "When stuff like this happens it's interesting. I feel bad for living in a house that's in their way."